Discarded pneumatic vehicle tires form a considerable resource. Patents intended to utilize this resource include U.S. Pat. Nos. 292,020; 1,285,992; 3,607,982; 3,753,821; 3,803,792; 3,819,915; 3,848,85; 3,934,540; 4,030,706; 4,186,913; 4,905,734; and 4,934,426 and German Patent 2,950,699 and United Kingdom Patents 1,368,772 and 2,207,349.